Arjun smiled. He’d read the PDF a dozen times, but paper was different. Paper let you wander. He turned to a random page: LED flasher for beginners . Then: Solar cell voltage booster . Then: Simple metal detector .

But the PDF was 800 MB, the lab Wi-Fi was a dying star, and his laptop battery was at 12%.

Twenty minutes later, the ancient lab printer coughed out 413 double-sided pages. Arjun stapled them into three sagging volumes. He wrote on the cover of Volume 2: MIMS – Opto & Magic .